Performance of Base and Shaft Grouted Steel Micropiles สมรรถนะของเสาเข็มไมโครไพล์เหล็กที่มีการอัดฉีดน้ำปูนที่ปลายและผิวข้าง

Abstract

This paper presented the results obtained from the performance of steel micropiles grouted with cement both at the base and along the shaft. The tested hollow steel piles were 9 cm. in diameter, 3 mm. thick, and 2 m. long. The study began by pressing the steel piles into the sand level at the depth of 1.80 m. Then, two types of test were performed, including a normal pile and a pile with both base and shaft grouts. For the latter, the grouting process was carried out using the pressure of 5 bars; the grout then was left for 28 days to set up. After that, pile load test was conducted according to the ASTM D 1143-81 standard. From the analysis of the ultimate load of pile capacity for the normal pile with respect to Davisson’s method, it was found that the ultimate pile capacity was 2.31 tons with the settlement of 5.75 mm. When employing Terzaghi’s method, however, the ultimate pile capacity and respective settlement were 2.58 tons and 9 mm. For the grouted pile, Davisson’s method yielded the ultimate pile capacity and settlement of 2.33 tons and 5.80 mm, respectively. For Terzaghi’s method, however, it was observed that the ultimate pile capacity was 2.61 tons, while its corresponding settlement was 9 mm. From these results, it indicated that the grouted steel pipe pile has greater ultimate pile capacity than that of the normal pile. This was because the grout adhered to the pile could increase the friction between surround soil and pile shaft thereby increased the pile capacity.